Perhaps baptism’s slammed in memoirs (9)
I believe the answer is:
immersion
'perhaps baptism's' is the definition.
I can't tell whether this definition defines the answer.
'slammed in memoirs' is the wordplay.
'slammed' is an anagram indicator.
'in'+'memoirs'='inmemoirs'
'inmemoirs' anagrammed gives 'IMMERSION'.
Can you help me to learn more?
(Other definitions for immersion that I've seen before include "dip" , "Deep absorption; baptism" , "Deep absorption (in a subject)" , "Baptism; deep involvement" .)